1. Field of the Invention
The present invention relates to a data communication apparatus which sets up a plurality of communication processes successively to communicate data.
2. Related Art
A conventional data communication apparatus such as, for example, a facsimile apparatus, performs only one procedure, e.g., a copying or a communication process, at a time. Recently, however, one facsimile apparatus which is able to make a reservation of other communication processes during one communication process, has been developed. This kind of facsimile apparatus has an image memory for storing a large amount of image data of documents to be sent, and makes a plurality of calls sending image data from the image memory. Using this basic feature, a sequential broad casting operation process can be performed.
However, in the above-mentioned facsimile apparatus, it is very difficult for the operator to confirm when a telephone line is being used for communication, because the image data is transmitted from the image memory. On the other hand, in a conventional facsimile apparatus where transmission from memory is not used, it is easy for the operator to recognize when the line is occupied simply by looking at the document being sent, because the document moves as it is read by a reading device during the communication process.
When the operator wants to use the telephone line, e.g., for making a call to speak with the operator on the other side or to make a call to send an urgent document, the operator has to choose a time when the facsimile apparatus has released the telephone line and has not occupied it for the next communication. Even with a display showing whether the telephone line is busy or not, the operator has to wait for the display changes to show that the line is not busy. If the line is busy for a long time, the operator cannot leave the apparatus for a long time.
This problem occurs not only with a facsimile apparatus but with other data communication apparatus such as those which are for communicating character code data, or numerical data. In these other types of data communication apparatus, the ease of handling and operation is deteriorating seriously with increasing machine complexity.
In other words, data communication apparatus of types which set up a plurality of calls successively are not capable of informing the operator as to when the operator will be able to use the line, and the operator cannot reserve time for that purpose for himself or herself. Therefore, the ease of handling and operation of the data communication apparatus is not fully satisfactory.